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arxiv: 2605.06549 · v1 · submitted 2026-05-07 · 🧮 math.OC

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Stochastic Non-Smooth Non-Convex Optimization with Decision-Dependent Distributions

Chengchang Liu, Haishan Ye, John C.S. Lui, Zongqi Wan

Pith reviewed 2026-05-08 07:58 UTC · model grok-4.3

classification 🧮 math.OC
keywords stochastic zeroth-order optimizationdecision-dependent distributionsnon-smooth non-convex optimizationGoldstein stationary pointsconvergence complexitysingle oracle queryHessian-Lipschitz objectives
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The pith

For non-smooth non-convex problems with decision-dependent distributions, a stochastic zeroth-order method finds (δ,ε)-Goldstein stationary points using O(d² δ^{-3} ε^{-3}) single-query oracle calls.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper shows how to optimize non-smooth non-convex functions when the only access is noisy function values and the distribution from which those values are drawn changes with the current decision. It gives an explicit rate to reach an approximate stationary point defined via the Goldstein notion, and proves the same rate works with only one oracle call per iteration. The analysis is then extended to smooth objectives and to objectives whose Hessians are Lipschitz, producing concrete complexity bounds in each case. A reader would care because many practical tasks, from simulation-based design to certain learning problems, naturally have both non-smoothness and decision-dependent noise, and zeroth-order methods are the only option when gradients cannot be computed.

Core claim

For non-smooth non-convex objectives with decision-dependent distributions, a stochastic zeroth-order method finds a (δ,ε)-Goldstein stationary point with SZO complexity O(d² δ^{-3} ε^{-3}) and does so with only one SZO feedback per iteration. The same framework yields complexity O(d² ε^{-6}) when the objective is smooth and O(d² ε^{-9/2}) when the objective is Hessian-Lipschitz, the latter improving the best-known ε dependence for decision-dependent zeroth-order methods by a factor of ε^{-1/2}.

What carries the argument

A single-call stochastic zeroth-order estimator that produces unbiased estimates of smoothed directional derivatives while controlling the bias introduced by the decision-dependent sampling law.

If this is right

  • Non-smooth non-convex problems with shifting distributions become tractable under single-query zeroth-order access.
  • The single-feedback property removes the need for multiple independent samples at each step.
  • Smooth problems admit an O(d² ε^{-6}) guarantee under the same decision-dependent model.
  • Hessian-Lipschitz problems admit an O(d² ε^{-9/2}) guarantee that is strictly better than prior decision-dependent zeroth-order bounds.
  • The rates are dimension-dependent only through a quadratic factor in d.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The single-query result suggests the approach could be plugged into expensive black-box simulators without doubling evaluation cost.
  • The improvement in the Hessian-Lipschitz regime hints that further smoothness assumptions may continue to reduce the exponent on ε.
  • Applications such as policy optimization in environments whose transition law depends on the chosen policy become directly addressable by these rates.

Load-bearing premise

The distribution from which samples are drawn changes continuously or with bounded moments when the decision variable changes.

What would settle it

A concrete counter-example in which the sampling distribution jumps discontinuously with the decision and the observed iteration count to reach the target (δ,ε) exceeds the stated bound by more than a constant factor.

Figures

Figures reproduced from arXiv: 2605.06549 by Chengchang Liu, Haishan Ye, John C.S. Lui, Zongqi Wan.

Figure 1
Figure 1. Figure 1: Strategic-classification train loss over oracle queries. view at source ↗
read the original abstract

We study stochastic zeroth-order optimization with decision-dependent distributions, where the sampling law depends on the current decision and only noisy function values are available. For the non-smooth non-convex setting, we establish an explicit convergence guarantee for finding a $(\delta,\epsilon)$-Goldstein stationary point with stochastic zeroth-order oracle (SZO) complexity of $\mathcal{O}(d^2\delta^{-3}\epsilon^{-3})$. In addition, we show that the above complexity can be achieved with single SZO feedback per iteration. We further extend the analysis to smooth and Hessian-Lipschitz objectives, obtaining complexities $\mathcal{O}(d^2\epsilon^{-6})$ and $\mathcal{O}(d^2\epsilon^{-9/2})$, respectively. In the Hessian-Lipschitz case, this improves the best-known dependence on $\epsilon$ for decision-dependent zeroth-order methods by a factor of $\epsilon^{-1/2}$.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript studies stochastic zeroth-order optimization (SZO) where the sampling distribution depends on the current decision variable and only noisy function values are available. For non-smooth non-convex objectives it establishes an explicit complexity of O(d² δ^{-3} ε^{-3}) to reach a (δ,ε)-Goldstein stationary point, achievable with a single SZO query per iteration. The analysis is extended to smooth objectives (O(d² ε^{-6})) and Hessian-Lipschitz objectives (O(d² ε^{-9/2})), the latter improving the best-known ε-dependence for decision-dependent zeroth-order methods by a factor of ε^{-1/2}.

Significance. If the stated rates hold under the paper's regularity conditions on the distribution map, the work supplies the first explicit SZO complexities for the non-smooth non-convex decision-dependent setting together with a single-query implementation and a concrete improvement in the Hessian-Lipschitz regime. These results are obtained by adapting standard one-point estimators while controlling the additional bias induced by distribution shift, which is a technically useful contribution for simulation-based and data-driven optimization problems.

major comments (2)
  1. [Theorem 3.2 and surrounding bias analysis] The single-SZO-per-iteration claim is central to the practical contribution. The proof must demonstrate that the bias term arising from the decision-dependent distribution shift remains controlled without requiring additional queries to estimate the distribution change; this control appears to rely on the Lipschitz continuity of the distribution map in total variation (or Wasserstein) distance together with uniform moment bounds, but the precise invocation of these assumptions in the one-point estimator analysis should be highlighted.
  2. [Section 5, Theorem 5.1] In the Hessian-Lipschitz extension the claimed O(d² ε^{-9/2}) rate improves prior work by ε^{-1/2}. The derivation of this improvement should be checked against the additional bias introduced by the decision-dependent sampling; if the improvement is obtained by a standard smoothing argument plus the distribution-Lipschitz assumption, the paper should state explicitly whether any extra logarithmic factors or dimension dependence appear.
minor comments (2)
  1. [Assumptions section] The precise regularity conditions on the decision-dependent distributions (Lipschitz continuity in total variation/Wasserstein distance and moment bounds) are stated in the full text but should be collected in a single assumption block immediately before the main theorems for easy reference.
  2. [Introduction] Notation for the Goldstein stationarity measure and the one-point estimator should be introduced with a short reminder in the introduction, as readers may not recall the exact definition of a (δ,ε)-Goldstein point.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the positive assessment and recommendation for minor revision. We address the two major comments below and will incorporate clarifications to improve the exposition.

read point-by-point responses
  1. Referee: [Theorem 3.2 and surrounding bias analysis] The single-SZO-per-iteration claim is central to the practical contribution. The proof must demonstrate that the bias term arising from the decision-dependent distribution shift remains controlled without requiring additional queries to estimate the distribution change; this control appears to rely on the Lipschitz continuity of the distribution map in total variation (or Wasserstein) distance together with uniform moment bounds, but the precise invocation of these assumptions in the one-point estimator analysis should be highlighted.

    Authors: We agree that explicit highlighting improves clarity. In the proof of Theorem 3.2 the bias is controlled via the total-variation Lipschitz continuity of the distribution map (Assumption 2.3) together with the uniform moment bounds (Assumption 2.2); these allow the one-point estimator to be analyzed directly without extra queries. We will add a short remark immediately after the bias bound to reference these two assumptions at the relevant steps. revision: yes

  2. Referee: [Section 5, Theorem 5.1] In the Hessian-Lipschitz extension the claimed O(d² ε^{-9/2}) rate improves prior work by ε^{-1/2}. The derivation of this improvement should be checked against the additional bias introduced by the decision-dependent sampling; if the improvement is obtained by a standard smoothing argument plus the distribution-Lipschitz assumption, the paper should state explicitly whether any extra logarithmic factors or dimension dependence appear.

    Authors: The ε^{-9/2} dependence is obtained by the standard Hessian-Lipschitz smoothing argument together with our existing bias-control lemma; the distribution-Lipschitz assumption absorbs the additional bias into terms that do not worsen the ε exponent and introduce neither extra logarithmic factors nor further dimension dependence beyond the O(d²) already present. We will insert a clarifying sentence in the paragraph following Theorem 5.1 stating this explicitly. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is self-contained

full rationale

The paper derives explicit SZO complexity bounds for reaching a (δ,ε)-Goldstein stationary point in the non-smooth non-convex case (and improved rates for smooth/Hessian-Lipschitz extensions) under decision-dependent distributions. These bounds are obtained by adapting standard one-point zeroth-order gradient estimators while controlling the additional bias induced by the distribution shift, using explicitly stated regularity conditions such as Lipschitz continuity of the distribution map in total variation or Wasserstein distance together with uniform moment bounds. The single-SZO-feedback-per-iteration claim is a direct consequence of the same analysis rather than an input assumption. No step reduces a claimed result to a fitted parameter, self-definition, or load-bearing self-citation chain; the argument is independent of the target complexities and relies on conventional proof techniques for zeroth-order stochastic optimization.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract provides no explicit free parameters, axioms, or invented entities; standard optimization assumptions such as bounded noise moments and decision-continuity of the distribution are likely required but unlisted.

pith-pipeline@v0.9.0 · 5462 in / 1138 out tokens · 53554 ms · 2026-05-08T07:58:36.307484+00:00 · methodology

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Reference graph

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